Securing the traffic between two mail servers is critical to maintaining privacy of electronic data and communications. For example, securing communications between two Exchange-brand servers can be particularly useful for individuals and organizations that routinely send and receive confidential information via electronic mail. Using a traditional SSL/TLS approach requires deploying a certificate based public key infrastructure (PKI) which is very complicated. This has proven to be a very large impediment for using SSL/TLS to secure SMTP (simple mail transfer protocol) traffic for many users of mail server, for example, Exchange-brand server.
Authentication can refer to the process of verifying the identity of a user that is logging onto a computer system or verifying the integrity of a transmitted message. In many cases, an authentication token is employed to facilitate the authentication process. For example, an authentication token can be passed to authorized users and retained in their possession for future access and/or transmission of electronic messages.
One common network authentication is the Kerberos authentication protocol. This particular protocol enables individuals that communicate over an insecure network to prove their identity to each other in a very secure manner. In addition to ensuring integrity of transmitted data, the Kerberos authentication protocol facilitates prevention of eavesdropping and/or replay attacks. Most often, the Kerberos protocol is employed in a client-server model where mutual authentication is provided by requiring both the user and the service to verify their respective identity.